Successful treatment of acute myocardial ischaemia with teopranitol--a novel organic nitrate

The present study was designed to examine the effects of a new organic nitrate, teopranitol, in acute myocardial ischaemia. Adult cats were subjected to 5 h of myocardial ischaemia by permanent ligation of the left anterior descending coronary artery (LAD). Teopranitol (10 mg kg-1 X h) or physiological saline (vehicle) was infused i.v., beginning 30 min after LAD occlusion and continued until the end of the experiment. All Animals subjected to myocardial ischaemia showed a significant elevation of the ST-segment within 20 min of LAD occlusion. In the LAD-vehicle group, the ST-segment elevation continued to increase; teopranitol attenuated this increase and significantly reduced the ST-segment elevation at 4 and 5 h (P less than 0.05). The loss of creatine phosphokinase-specific activity from the ischaemic myocardium was significantly reduced by teopranitol (P less than 0.05), indicating an improved preservation of myocardial tissue. There was a significant initial reduction in mean arterial blood pressure by teopranitol in sham-operated cats but no consistent change of this parameter, heart rate or the computed pressure-rate product in LAD-occluded cats. Teopranitol did completely reverse the ischaemia induced formation of platelet aggregates at 1 to 5 h (P less than 0.05). It is concluded that teopranitol exerts a significant protective effect in acute myocardial ischaemia in vivo that is independent of changes in systemic haemodynamics and might be associated with the generation of an antiplatelet activity in vivo.